Performance Enhancement of GaN-Based Laser Diodes With Prestrained Growth

Effects of the prestrained growth of a low-In InGaN/GaN quantum well (QW) before the designated light-emitting high-In InGaN/GaN multi quantum wells (MQWs) in GaN-based laser diodes (LDs) are numerically investigated. Simulation results show that the inserted low-In InGaN/GaN QW does not remarkably change the absorption loss, and the ratio of recombination current of low-In InGaN/GaN QW over injection current is very small, especially after LD is lasing. However, it weakens the polarization fields, resulting in less tilted energy bands, and the overlap of electron–hole pairs is greatly increased, which reduces threshold carrier concentrations of MQWs, leakage current, and nonradiative recombination. The performance of LD is enhanced. Threshold current is reduced by 19%, and output power is increased by 59% at the injection current of 120 mA.